Enable Python 3 tests by default in Tox config
Enable Python 3 tests by default in Tox config

Now that we're supporting it, I plan to run the Python 3 tests as part of
my normal coding workflow.

mosesfistos1/beetbox,beetbox/beets,diego-plan9/beets,artemutin/beets,madmouser1/beets,SusannaMaria/beets,SusannaMaria/beets,mosesfistos1/beetbox,madmouser1/beets,sampsyo/beets,jackwilsdon/beets,xsteadfastx/beets,lengtche/beets,jackwilsdon/beets,diego-plan9/beets,diego-plan9/beets,beetbox/beets,ibmibmibm/beets,mosesfistos1/beetbox,xsteadfastx/beets,lengtche/beets,MyTunesFreeMusic/privacy-policy,artemutin/beets,jackwilsdon/beets,sampsyo/beets,madmouser1/beets,lengtche/beets,Kraymer/beets,shamangeorge/beets,sampsyo/beets,shamangeorge/beets,sampsyo/beets,beetbox/beets,jackwilsdon/beets,MyTunesFreeMusic/privacy-policy,pkess/beets,xsteadfastx/beets,SusannaMaria/beets,lengtche/beets,MyTunesFreeMusic/privacy-policy,ibmibmibm/beets,xsteadfastx/beets,beetbox/beets,madmouser1/beets,artemutin/beets,mosesfistos1/beetbox,Kraymer/beets,pkess/beets,SusannaMaria/beets,diego-plan9/beets,artemutin/beets,Kraymer/beets,ibmibmibm/beets,shamangeorge/beets,ibmibmibm/beets,pkess/beets,shamangeorge/beets,pkess/beets,MyTunesFreeMusic/privacy-policy,Kraymer/beets